Because you don't own any of those things. If you own your own plane and have a pilot's license, you are more than welcome to fly it yourself and to disengage the autopilot should the situation demand it.

I wouldn't mind an autonomous car-share service. Just saying that Musk's futurist vision of mandatory self-driving vehicles is incompatible with personal control of personal technology, and practically, politically infeasible in the US anytime soon.